Typically, automotive interior plastic parts are painted after they are molded. The painting process requires elaborate facilities and consequently necessitates large expenses. For instance, significant square footage of a factory must be dedicated to a clean room environment for the spraying of paint and clear coat and for the baking and curing of paint on components, such as those components used in the automotive industry, such as body panels, air bag covers, instrument panels and the like. Moreover, solvent-based paints have in recent years raised significant environmental concerns because of the volatile organic components which are emitted into the air during the application of such solvent-based paints. As a result, the evaporation of such solvents must be strictly monitored to satisfy environmental and safety regulations.
In addition, automotive components, especially interior automotive components, are strictly scrutinized following the painting process in order to match or conform the automotive component to the styling and aesthetic requirements of the associated interior trim product. Painting such automotive components following the molding process, raises quality concerns with respect to the color, consistency, and thickness of each individual paint application.
U.S. Pat. No. 5,678,851 to Saito et al. discloses an air bag module cover including an ornament on a cover member. The ornament may be made from a resin material with a metal foil.
U.S. Pat. No. 4,902,557, the Rohrbacher reference discloses a method and apparatus for manufacturing a thermoplastic polyolefin composite useful as an exterior auto or truck body part.
U.S. Pat. No. 4,769,100, the Short reference, teaches a method of applying a carrier film pre-printed with metallic paint to an automobile body panel in a vacuum forming process.
U.S. Pat. No. 4,952,351 and U.S. Pat. No. 5,466,412, the Parker patents, teach a method of manufacturing an air bag cover for an inflatable air bag system including a bondable film carrier, which is painted after the film carrier is molded.
Hot stamping is utilized for plastic decorating. For example, U.S. Pat. No. 5,769,548 discloses a hot stamp imprinting system with latchable ink ribbon cassette and handle.
Presently, when air bag covers are provided in automobiles on the driver's side of the vehicle, the air bag is stored in the steering column behind an air bag cover. During automatic inflation of the air bag, the air bag cover moves away from the steering column to permit its safety function between the steering column and the operator of the vehicle.
Recent practice in the automotive industry is utilization of all plastic fabricated air bag covers. It is known in other automotive parts areas that different, aesthetically pleasing outer surfaces enhance the overall appearance of the interior of automotive vehicles. Use of decorative appliques having solid colors contrasting or blending with the different colors of the plastic air bag covers is often sought after. Simulated wood grain finishes, and metallic finishes are also popular and economically feasible in combination with various plastic automotive parts.
Difficulties are known to arise in properly applying applique films to annular or arcuate plastic outer surfaces. Applique films are usually approximately 0.5 millimeters thick or less and are therefore not easily applied directly to an outer air bag cover surface. Improper application causes small air pockets to occur on the decorative film which often makes the resultant air bag cover, unattractive and thus unusable. Additionally, conventional air bag covers invariably include annular or arcuate surfaces, and affixing the thin applique film to these designated surfaces is even more difficult.
The deposition or fastening of the applique must be perfected with a method that affords a smooth surface and neat appearance. Thus it is known to utilize a backing material or liner in conjunction with a thin applique film to afford a clean, smooth appearance of the final product.
In addition, the applique must be affixed to the front cover in such a way as to prevent the applique from separating from the front cover when the air bag deploys. The applique must therefore be bonded to the front cover with sufficient strength to prevent fragmentation of the applique during air bag inflation and exit.
The U.S. patents to Eckout 5,487,557 and 5,529,336 disclose an automotive air bag cover having a decorative applique fastened thereto. The air bag cover is manufactured from plastic and includes a front panel adapted to enclose an uninflated automotive air bag. The front panel includes inner and outer surfaces. Side panels are further provided and are connected to and extend from the front panel. The decorative applique is fastened to the outer surface of the front cover by a plurality of connecting towers which extend through the front cover. Seams are provided for permitting the air bag to inflate and exit the front cover. The decorative applique is fastened to the front cover adjacent the seams in a non-overlapping fashion such that the decorative applique does not interfere with exit or inflation of the air bag.
However, the prior art fails to provide a foil-covered automotive interior plastic part having a decorative preform and method of making same wherein hot stamping is used and wherein the foil is bonded to a substrate of the plastic part so as to have the durability and strength necessary to support varying applications yet comply with styling and aesthetic requirements.